We report the magnetic anisotropy of kagome bilayer ferromagnet Fe3Sn probed by the bulk magnetom... more We report the magnetic anisotropy of kagome bilayer ferromagnet Fe3Sn probed by the bulk magnetometry and magnetic force microscopy (MFM) on high-quality single crystals. The dependence of magnetization on the orientation of the external magnetic field reveals strong easy-plane magnetocrystalline anisotropy and anisotropy of the saturation magnetization. The leading magnetocrystalline anisotropy constant shows a monotonous increase from K1≈−1.0×106 J/m3 at 300 K to −1.3×106 J/m3 at 2 K. Our ab initio electronic structure calculations yield the value of total magnetic moment of 7.1 μB/f.u. and a magnetocrystalline anisotropy energy density of −0.57 meV/f.u. (−1.62×106J/m3) both being in reasonable agreement with the experimental values. The MFM imaging reveals micrometer-scale magnetic vortices with weakly pinned cores that vanish at the saturation field of ∼3 T applied perpendicular to the kagome plane. The observed vortex-domain structure is well reproduced by the micromagnetic sim...
Spin-orbit quartet ground states are associated with rich phenomenology, ranging from multipolar ... more Spin-orbit quartet ground states are associated with rich phenomenology, ranging from multipolar phases in f1 rare-earth borides to magnetism emerging through covalency and vibronic couplings in d1 transition-metal compounds. The latter effect has been studied since the 1960s on t2g1 octahedral ML6 units in both molecular complexes and extended solid-state lattices. Here we analyze the Jeff = 3/2 quartet ground state of larger cubane-like M4L4 entities in lacunar spinels, composed of transition-metal (M) tetrahedra caged by chalcogenide ligands (L). These represent a unique platform where spin-orbit coupling acts on molecular-like, delocalized t2 orbitals. Using quantum chemical methods, we pin down the interplay of spin-orbit couplings in such a setting and many-body physics related to other molecular-like single-electron levels, both below and above the reference t21. We provide a different interpretation of resonant inelastic X-ray scattering data on GaTa4Se8 and, by comparing magnetic susceptibility data with calculated g factors, valuable insights into the important role of vibronic couplings.
Fe3Sn2 Markus Altthaler, 2, 3, ∗ Erik Lysne, 3, ∗ Erik Roede, Lilian Prodan, Vladimir Tsurkan, 4 ... more Fe3Sn2 Markus Altthaler, 2, 3, ∗ Erik Lysne, 3, ∗ Erik Roede, Lilian Prodan, Vladimir Tsurkan, 4 Mohamed A. Kassem, Stephan Krohns, István Kézsmárki, † and Dennis Meier 3, ‡ Experimental Physics V, University of Augsburg, 86135 Augsburg, Germany Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), 7043 Trondheim, Norway Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway Institute for Applied Physics, MD-2028, Chisinau, Moldova Department of Physics, Assiut University, 171516 Assiut, Egypt (Dated: June 17, 2021)
Frustrated magnets provide a promising avenue for realizing exotic quantum states of matter, such... more Frustrated magnets provide a promising avenue for realizing exotic quantum states of matter, such as spin liquids and spin ice or complex spin molecules. Under an external magnetic field, frustrated magnets can exhibit fractional magnetization plateaus related to definite spin patterns stabilized by field-induced lattice distortions. Magnetization and ultrasound experiments in MnCr2S4 up to 60 T reveal two fascinating features: (i) an extremely robust magnetization plateau with an unusual spin structure and (ii) two intermediate phases, indicating possible realizations of supersolid phases. The magnetization plateau characterizes fully polarized chromium moments, without any contributions from manganese spins. At 40 T, the middle of the plateau, a regime evolves, where sound waves propagate almost without dissipation. The external magnetic field exactly compensates the Cr-Mn exchange field and decouples Mn and Cr sublattices. In analogy to predictions of quantum lattice-gas models, ...
We report the magnetic anisotropy of kagome bilayer ferromagnet Fe3Sn probed by the bulk magnetom... more We report the magnetic anisotropy of kagome bilayer ferromagnet Fe3Sn probed by the bulk magnetometry and magnetic force microscopy (MFM) on high-quality single crystals. The dependence of magnetization on the orientation of the external magnetic field reveals strong easy-plane magnetocrystalline anisotropy and anisotropy of the saturation magnetization. The leading magnetocrystalline anisotropy constant shows a monotonous increase from K1≈−1.0×106 J/m3 at 300 K to −1.3×106 J/m3 at 2 K. Our ab initio electronic structure calculations yield the value of total magnetic moment of 7.1 μB/f.u. and a magnetocrystalline anisotropy energy density of −0.57 meV/f.u. (−1.62×106J/m3) both being in reasonable agreement with the experimental values. The MFM imaging reveals micrometer-scale magnetic vortices with weakly pinned cores that vanish at the saturation field of ∼3 T applied perpendicular to the kagome plane. The observed vortex-domain structure is well reproduced by the micromagnetic sim...
Spin-orbit quartet ground states are associated with rich phenomenology, ranging from multipolar ... more Spin-orbit quartet ground states are associated with rich phenomenology, ranging from multipolar phases in f1 rare-earth borides to magnetism emerging through covalency and vibronic couplings in d1 transition-metal compounds. The latter effect has been studied since the 1960s on t2g1 octahedral ML6 units in both molecular complexes and extended solid-state lattices. Here we analyze the Jeff = 3/2 quartet ground state of larger cubane-like M4L4 entities in lacunar spinels, composed of transition-metal (M) tetrahedra caged by chalcogenide ligands (L). These represent a unique platform where spin-orbit coupling acts on molecular-like, delocalized t2 orbitals. Using quantum chemical methods, we pin down the interplay of spin-orbit couplings in such a setting and many-body physics related to other molecular-like single-electron levels, both below and above the reference t21. We provide a different interpretation of resonant inelastic X-ray scattering data on GaTa4Se8 and, by comparing magnetic susceptibility data with calculated g factors, valuable insights into the important role of vibronic couplings.
Fe3Sn2 Markus Altthaler, 2, 3, ∗ Erik Lysne, 3, ∗ Erik Roede, Lilian Prodan, Vladimir Tsurkan, 4 ... more Fe3Sn2 Markus Altthaler, 2, 3, ∗ Erik Lysne, 3, ∗ Erik Roede, Lilian Prodan, Vladimir Tsurkan, 4 Mohamed A. Kassem, Stephan Krohns, István Kézsmárki, † and Dennis Meier 3, ‡ Experimental Physics V, University of Augsburg, 86135 Augsburg, Germany Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), 7043 Trondheim, Norway Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway Institute for Applied Physics, MD-2028, Chisinau, Moldova Department of Physics, Assiut University, 171516 Assiut, Egypt (Dated: June 17, 2021)
Frustrated magnets provide a promising avenue for realizing exotic quantum states of matter, such... more Frustrated magnets provide a promising avenue for realizing exotic quantum states of matter, such as spin liquids and spin ice or complex spin molecules. Under an external magnetic field, frustrated magnets can exhibit fractional magnetization plateaus related to definite spin patterns stabilized by field-induced lattice distortions. Magnetization and ultrasound experiments in MnCr2S4 up to 60 T reveal two fascinating features: (i) an extremely robust magnetization plateau with an unusual spin structure and (ii) two intermediate phases, indicating possible realizations of supersolid phases. The magnetization plateau characterizes fully polarized chromium moments, without any contributions from manganese spins. At 40 T, the middle of the plateau, a regime evolves, where sound waves propagate almost without dissipation. The external magnetic field exactly compensates the Cr-Mn exchange field and decouples Mn and Cr sublattices. In analogy to predictions of quantum lattice-gas models, ...
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Papers by Lilian Prodan